The present invention relates to electrical devices, and, more particularly, to electrical outlet boxes.
Electrical outlet or junction boxes are commonly, if not universally, used in. residential and commercial buildings as a means for holding electrical devices (outlets, switches, etc.), and for holding and/or guiding the electrical wires or cables that are attached to the electrical devices. Electrical outlet boxes typically comprise a rectangular, square, or octagonal metal or plastic xe2x80x9cboxxe2x80x9d having one open side and a plurality of knockouts (partially stamped or scored portions that can be easily removed to form conduit or cable through-holes) on the other sides. Outlet boxes can be attached directly to a wall (xe2x80x9csurface mounting,xe2x80x9d oftentimes used in industrial settings), or they can be attached to the sides of a wall""s metal or wood support members (studs or joists), with the interior of the outlet box being exposed by way of a hole in the wall covering (xe2x80x9cflush mountingxe2x80x9d).
For flush mount applications, the electrical outlet box must be somehow fastened to the side of a stud or joist. Frequently, this is done by angling a fastener screw or the like through the open front of the box, through an angled fastener aperture provided in one of the box""s sides, and into the stud or joist. U.S. Pat. No. 6,100,469 to Jorgensen et al. shows such an outlet box. Alternatively, separate mounting brackets can be used, as shown in U.S. Pat. No. 4,572,391 to Medlin, or the electrical box can be provided with external mounting wings or brackets, as shown in U.S. Pat. No. 6,198,045 to Roesch.
While these attachment mechanisms are functional, they suffer from certain drawbacks. For example, angled fasteners do not work well with metal studs, require significant precision, and are relatively time consuming to use, while separate brackets can increase both cost and time (i.e., a separate bracket has to be purchased, which then has to be separately attached to both the box and stud). If the bracket is pre-attached, it must be set at the correct depth for the wall finish contemplated, leading to an inventory problem of many different preset depth box variations. Also, external mounting wings or brackets increase manufacturing costs, and, since they extend beyond the box body itself and are relatively bulky, greatly limit how the box can be oriented for attachment to a wall stud. This can be especially problematic when cables or conduit come at the outlet box at a particular angle, e.g., at a side where the box might not have the proper series of knockouts, if any at all, or the access is inhibited by the pre-attached bracket.
More specifically, in wiring most modem buildings, there is oftentimes a mix of various types of wiring (armored or sheathed electrical cable, conduit, data lines, etc.), all of which may need to be routed to and/or through an outlet or junction box. Moreover, conduit is typically rigid, and cannot be bent in a small radius to accommodate misaligned conduit knockouts. Unfortunately, most electrical outlet boxes cannot easily handle a mix of multiple cables and conduit, and, even if they can, are relatively inflexible in terms of cable/conduit placement, e.g., the box can only accommodate vertical or horizontal conduit, but not both, or cable runs must be made up to look like conduit (box connectors).
Finally, many outlet boxes include cable clamps, which are attached to the outlet box by a screw extending through the clamp, through a tapped hole in the box, and out the back of the box. Ground screws, by which a ground wire is affixed to the box, also typically project past the back of the box. This can be a problem when the excess, projecting thread hits another box (in back-to-back mountings), or hits a hard surface like a masonry block wall.
Accordingly, a primary object of the present invention is to provide an electrical outlet or junction box that can be quickly and easily affixed to the side of a stud or joist, and especially to metal studs.
Another primary object of the present invention is to provide an electrical outlet or junction box that can be oriented to align with incoming conduit while still accommodating a mix of multiple cables and conduits.
Another object of the present invention is to provide an electrical outlet or junction box that has screws extending inward for ground and cable clamp retention, so as to eliminate excess thread extending past the back of the box.
Another object of the present invention is to provide an outlet box having enough volume in the box to allow for up to four typical cables to enter from one side.
A rapid mounting, xe2x80x9csquarexe2x80x9d electrical outlet or junction box (4xe2x80x3 square, 4-{fraction (11/16)}xe2x80x3 square, 2-gang, etc.) comprises a back plate and four upstanding sidewalls attached to the back plate and defining a front opening. One or more of the sidewalls has a number of xc2xd or xc2xexe2x80x3 conduit knockouts, as well as (optionally) a plurality of cable access ports, which allow entry of AC, MC, NM, or other cables. The sidewalls also have a mounting hole pattern for mounting the outlet box. In one version, for each pair of opposing sidewalls, the mounting hole pattern comprises a pair of guide holes, large enough to pass a screw and driver bit, on one sidewall, and a pair of aligning fastener apertures, only large enough to pass a screw shank, on the opposing sidewall. In a second version, for each pair of opposing sidewalls, the mounting hole pattern comprises two guide holes and two fastener apertures on each sidewall, wherein the guide holes on each sidewall align with the fastener apertures on the opposite sidewall. In both versions, the aligned mounting holes extending through the sides of the outlet box permit the box to be rapidly attached to a stud with standard screws and a power screwdriver. Since the mounting holes are not angled and no attachment brackets are required, the outlet box is especially adapted for use with metal studs and self tapping/drilling screws.
Also, because the mounting hole pattern (guide holes and fastener apertures) is repeated on both pairs of opposing sidewalls, the outlet box can be mounted to the right or left side of a stud, while still enabling the box sidewall(s) with the cable access ports to be accessible, e.g., facing up, down, or to the side. Accordingly, regardless of the box""s orientation, electrical cables can always be routed to the box, while conduits can be routed to either the top, left or right sides (through a hole in the stud, if needed), or bottom side. Thus, conduits that approach the box from any direction can be easily accommodated without bending or rerouting.
The outlet box may also have the following optional features: cable clamps; clamp shelves for mounting cable clamps on the outside of the outlet box; fold-out depth tangs for quickly positioning the outlet box against a stud at the proper depth (with respect to the stud and wall finish); device connection flanges across the top and bottom of the box""s front opening, which provide a number of different bolt patterns for connecting different types of electrical devices to the outlet box; and ground leads pre-electrically attached to the outlet box for quickly connecting the outlet box to an external ground wire via a wire nut or the like.